D. S. Rosero

Peroxidised dietary lipids impair intestinal function and morphology of the small intestine villi of nursery pigs in a dose-dependent manner

The objective of this study was to investigate the effect of increasing degrees of lipid peroxidation on structure and function of the small intestine of nursery pigs. A total of 216 pigs (mean body weight was 6·5 kg) were randomly allotted within weight blocks and sex and fed one of five experimental diets for 35 d (eleven pens per treatment with three to four pigs per pen). Treatments included a control diet without added lipid, and diets supplemented with 6 % soyabean oil that was exposed to heat (80°C) and constant oxygen flow (1 litre/min) for 0, 6, 9 and 12 d. Increasing lipid peroxidation linearly reduced feed intake (P<0·001) and weight gain (P=0·024). Apparent faecal digestibility of gross energy (P=0·001) and fat (P<0·001) decreased linearly as the degree of peroxidation increased. Absorption of mannitol (linear, P=0·097) and d-xylose (linear, P=0·089), measured in serum 2 h post gavage with a solution containing 0·2 g/ml of d-xylose and 0·3 g/ml of mannitol, tended to decrease progressively as the peroxidation level increased. Increasing peroxidation also resulted in increased villi height (linear, P<0·001) and crypt depth (quadratic, P=0·005) in the jejunum. Increasing peroxidation increased malondialdehyde concentrations (quadratic, P=0·035) and reduced the total antioxidant capacity (linear, P=0·044) in the jejunal mucosa. In conclusion, lipid peroxidation progressively diminished animal performance and modified the function and morphology of the small intestine of nursery pigs. Detrimental effects were related with the disruption of redox environment of the intestinal mucosa.

Sow and litter response to supplemental dietary fat in lactation diets during high ambient temperatures

The objective of this experiment was to determine the impact of supplemental dietary fat on total lactation energy intake and sow and litter performance during high ambient temperatures (27 ± 3°C). Data were collected from 337 mixed-parity sows from July to September in a 2,600-sow commercial unit in Oklahoma. Diets were corn-soybean meal-based with 7.5% corn distillers dried grains with solubles and 6.0% wheat middlings and contained 3.24 g of standardized ileal digestible Lys/Mcal of ME. Animal-vegetable fat blend (A-V) was supplemented at 0, 2, 4, or 6%. Sows were balanced by parity, with 113, 109, and 115 sows representing parity 1, 2, and 3 to 7 (P3+), respectively. Feed disappearance (subset of 190 sows; 4.08, 4.18, 4.44, and 4.34 kg/d, for 0, 2, 4, and 6%, respectively; P < 0.05) and apparent caloric intake (12.83, 13.54, 14.78, and 14.89 Mcal of ME/d, respectively; P < 0.001) increased linearly with increasing dietary fat. Gain:feed (sow and litter BW gain relative to feed intake) was not affected (P = 0.56), but gain:Mcal ME declined linearly with the addition of A-V (0.16, 0.15, 0.15, and 0.14 for 0, 2, 4, and 6%, respectively; P < 0.01). Parity 1 sows (3.95 kg/d) had less (P < 0.05) feed disappearance than P2 (4.48 kg/d) and P3+ (4.34 kg/d) sows. Body weight change in P1 sows was greater (P < 0.01) than either P2 or P3+ sows (-0.32 vs. -0.07 and 0.12 kg/d), whereas backfat loss was less (P < 0.05) and loin depth gain was greater (P < 0.05) in P3+ sows compared with P1 and P2 sows. Dietary A-V improved litter ADG (P < 0.05; 1.95, 2.13, 2.07, and 2.31 kg/d for 0, 2, 4, and 6% fat, respectively) only in P3+ sows. Sows bred within 8 d after weaning (58.3, 72.0, 70.2, and 74.7% for 0, 2, 4, and 6%, respectively); conception rate (78.5, 89.5, 89.2, and 85.7%) and farrowing rate (71.4, 81.4, 85.5, and 78.6%) were improved (P < 0.01) by additional A-V, but weaning-to-breeding interval was not affected. Rectal and skin temperature and respiration rate of sows were greater (P < 0.002) when measured at wk 3 compared with wk 1 of lactation, but were not affected by A-V addition. Parity 3+ sows had lower (P < 0.05) rectal temperature than P1 and P2 sows, and respiration rate was reduced (P < 0.001) in P1 sows compared with P2 and P3+ sows. In conclusion, A-V improved feed disappearance and caloric intake, resulting in improved litter weight gain and subsequent reproductive performance of sows; however, feed and caloric efficiency were negatively affected.

Development of prediction equations to estimate the apparent digestible energy content of lipids when fed to lactating sows 1

Two studies were conducted 1) to determine the effects of free fatty acid (FFA) concentrations and the degree of saturation of lipids (unsaturated to saturated fatty acids ratio [U:S]) on apparent total tract digestibility (ATTD) and DE content of lipids and 2) to derive prediction equations to estimate the DE content of lipids when added to lactating sow diets. In Exp. 1, 85 lactating sows were assigned randomly to a 4 × 5 factorial arrangement of treatments plus a control diet with no added lipid. Factors included 1) FFA concentrations of 0, 18, 36, and 54% and 2) U:S of 2.0, 2.8, 3.5, 4.2, and 4.9. Diets were corn-soybean meal based and lipid was supplemented at 6%. Concentrations of FFA and U:S were obtained by blending 4 lipid sources: choice white grease (CWG; FFA = 0.3% and U:S = 2.0), soybean oil (FFA = 0.1% and U:S = 5.5), CWG acid oil (FFA = 57.8% and U:S = 2.1), and soybean-cottonseed acid oil (FFA = 67.5% and U:S = 3.8). Titanium dioxide was added to diets (0.5%) as a digestibility marker. Treatments started on d 4 of lactation and fecal samples were collected after 6 d of adaptation to diets on a daily basis from d 10 to 13. The ATTD of added lipid and DE content of lipids were negatively affected (linear, < 0.001) with increasing FFA concentrations, but negative effects were less pronounced with increasing U:S (interaction, < 0.05). Coefficients of ATTD for the added lipid and DE content of lipids increased with increasing U:S (quadratic, = 0.001), but these improvements were less pronounced when the FFA concentration was less than 36%. Digestible energy content of added lipid was described by DE (kcal/kg) = [8,381 - (80.6 × FFA) + (0.4 × FFA) + (248.8 × U:S) - (28.1 × U:S) + (12.8 × FFA × U:S)] ( = 0.74). This prediction equation was validated in Exp. 2, in which 24 lactating sows were fed diets supplemented with 6% of either an animal-vegetable blend (A-V; FFA = 14.5% and U:S = 2.3) or CWG (FFA = 3.7% and U:S = 1.5) plus a control diet with no added lipids. Digestible energy content of A-V (8,317 and 8,127 kcal/kg for measured and predicted values, respectively) and CWG (8,452 and 8,468 kcal/kg for measured and predicted values, respectively) were accurately estimated using the proposed equation. The proposed equation involving FFA concentration and U:S resulted in highly accurate estimations of DE content (relative error, +0.2 to -2.3%) of commercial sources of lipids for lactating sows.

Impact of dietary lipids on sow milk composition and balance of essential fatty acids during lactation in prolific sows.

Two studies were designed to determine the effects of supplementing diets with lipid sources of EFA (linoleic and α-linolenic acid) on sow milk composition to estimate the balance of EFA for sows nursing large litters. In Exp. 1, 30 sows, equally balanced by parity (1 and 3 to 5) and nursing 12 pigs, were fed diets supplemented with 6% animal-vegetable blend (A-V), 6% choice white grease (CWG), or a control diet without added lipid. Diets were corn-soybean meal based with 8% corn distiller dried grains with solubles and 6% wheat middlings and contained 3.25 g standardized ileal digestible Lys/Mcal ME. Sows fed lipid-supplemented diets secreted greater amounts of fat (P = 0.082; 499 and 559 g/d for control and lipid-added diets, respectively) than sows fed the control diet. The balance of EFA was computed as apparent ileal digestible intake of EFA minus the outflow of EFA in milk. For sows fed the control diet, the amount of linoleic acid secreted in milk was greater than the amount consumed, throughout lactation. This resulted in a pronounced negative balance of linoleic acid (-22.4, -38.0, and -14.1 g/d for d 3, 10, and 17 of lactation, respectively). In Exp. 2, 50 sows, equally balanced by parity and nursing 12 pigs, were randomly assigned to a 2 × 2 factorial arrangement of diets plus a control diet without added lipids. Factors included linoleic acid (2.1% and 3.3%) and α-linolenic acid (0.15% and 0.45%). The different concentrations of EFA were obtained by adding 4% of different mixtures of canola, corn, and flaxseed oils to diets. The n-6 to n-3 fatty acid ratios in the diets ranged from 5 to 22. Increasing supplemental EFA increased (P < 0.001) milk concentrations of linoleic (16.7% and 20.8%, for 2.1% and 3.3% linoleic acid, respectively) and α-linolenic acid (P < 0.001; 1.1 and 1.9% for 0.15 and 0.45% α-linolenic acid, respectively). Increasing supplemental EFA increased the estimated balance of α-linolenic acid (P < 0.001; -0.2 and 5.3 g/d for 0.15% and 0.45% α-linolenic acid, respectively), but not linoleic acid (P = 0.14; -3.4 and 10.0 g/d for 2.1% and 3.3% linoleic acid, respectively). In conclusion, lipid supplementation to sow lactation diets improved milk fat secretion. The fatty acid composition of milk fat reflected the dietary supplementation of EFA. The net effect of supplemental EFA was to create a positive balance during lactation, which may prove to be beneficial for the development of nursing piglets and the subsequent reproduction of sows.

Essential fatty acid supplementation during lactation is required to maximize the subsequent reproductive performance of the modern sow

This study was conducted to investigate the effects of supplemental essential fatty acids (EFA) on sow reproductive efficiency and to estimate the concentrations of EFA required by the lactating sow for maximum subsequent reproduction. Data were collected on 480 sows (PIC Camborough) balanced by parity, with 241 and 239 sows representing Parity 1, and 3-5 (P3+), respectively. Sows were assigned randomly, within parity, to a 3 × 3 factorial arrangement plus a control diet without added lipids. Factors included linoleic (2.1%, 2.7%, and 3.3%) and α-linolenic acid (0.15%, 0.30%, and 0.45%), obtained by adding 4% of different mixtures of canola, corn and flaxseed oils to diets. Diets were corn-soybean meal based with 12% wheat middlings. The benefits of supplemental EFA were more evident for the subsequent reproduction of mature P3+ sows. For these sows, supplemental α-linolenic acid improved the proportion of sows that farrowed relative to sows weaned (linear P=0.080; 82.8, 80.5, and 92.8% for sows fed 0.15%, 0.30%, and 0.45% α-linolenic acid, respectively). In addition, supplemental linoleic acid, fed to Parity 1 and P3+ sows, tended to increase subsequent litter size (linear P=0.074; 13.2, 13.8 and 14.0 total pigs born for 2.1%, 2.7% and 3.3% linoleic acid, respectively). These results demonstrate that a minimum dietary intake of both α-linolenic and linoleic acid is required for the modern lactating sow to achieve a maximum reproductive outcome through multiple mechanisms that include rapid return to estrus, increased maintenance of pregnancy and improved subsequent litter size.